Horizontal arc-lamp.



H. W. HOBBS.

HORIZONTAL ARG LAMP.

APPLIOATION FILED FEB. 24, 1910.

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HNRY W'. HOBBS, OF PORTLAND, MAINE.

HORIZONTAL ARC-LAMP.

Specification of Letters Patent.

Patented Mar. 23, 1915.

Application filed February 24, 1910. Serial No. 545,626.

T0 all whom it may concern:

Be it known that I, HENRY W. HoBBs, a citizen of the United States, residing at Portland, in the county of Cumberland and State of Maine, have invented-certain new and useful Improvements in Horizontal Arc-Lamps, of which the following -is a specification.

This invention relates to means for automatically regulating the carbons of electric arc lights, particularly search lights, and in a general way the invention comprises an arc circuit having two carbons therein and means for adjusting them, a motor circuit, two electric motors in circuit therewith, one having a stationary field magnet and the other a rotary field magnet, the former having a rotary armature fixed to the field inagnet of the latter and the latter having a freely rotary armature, or any equivalent arrangement of the magnets and armatures, suitable electric connections for permitting the I current to rotate the armature of the first motor and to cause the armature of the second motor to remain stationary as long as the voltage across the arc remains constant and to rotate in either direction for the `pur- Y pose of regulating according as the voltage varies, means for automatically and quickly separating the carbons, means for preventing jamming of the arc'regulating mechanism, and means for automatically opening` the motor circuit when the arc circuit is opened.

The figure is a representation of one embodiment of my invention, partly in elevation, partly in vertical section and partly in diagram.

Any suitable type of direct current electric motor may be employed and only so much thereof is shown as is necessary to illustrate the invention. y

In the drawing 2 and 3 are electric motors. Motor 2 comprises a stationary field magnet 8 and a revoluble armature 9 permanently attached to one of the elements of motor 3 in any convenient manner, as shown by connecting spokes or ribs 11. Motor 3 comprises a field magnet 10 and an armature 12, both rotary. The armature 12 of 18 secured to the bearing armature 9 of motor 2 is provided with a commutator 16 having stationary brushes 1"?. The armature 12 of motor 3 is provided with a commutator 19 having brushes a 15. Commutator 16 is designed to commutate the current for armature 9 and commutator 19 is designed to commutate the current for armature 12. Motor 2 is a shunt motor, and motor 3 is a similar motor with the'addition of an extra set of field magnet coils connected in shunt with the arc circuit. A series of collector rings 20, 21, 22, 23 and 24 carried by field magnet 10 serves for currents passing through motor 3. Shaft 13 is provided with a gear 39 in mesh with a gear 38 on a threaded shaft 37 on which is' mounted the carbon supporting arm 36 which arm supports the positive carbon 32 of the lamp. Gear 38 in turn meshes with a gear 35 on a threaded shaft 34, on which is mounted the carbon supporting arm 33 which supports the negative carbon 31 of the lamp. Connected with the motor circuit is a magnetic clutch 40, one element of which is rigidly secured to gear 39, said gear 39 being normally loose on its shaft. vWhen the motor circuit is closed, the clutch coil becomes enei'gized and attracts its armature 41 splined on shaft 13, locking gear 39 to shaft 13 which then rotates with armature 12, which is then rotatable in either direction, according as the voltage across the arc varies, and thereby causing the carbons to approach or recede according Ato the direction in which the armature 12 rotates.

In practical operation the carbons are first brought into touch momentarily to draw the arc and then are separated a definite'disu however, there is an appreciable time required to effect a separation of the carbons and to expedite this I introduce into the arc circuit an electromagnet 43. A pivoted lever 44 has one end secured to the armature of magnet 43 which armature is held normally separated from the magnet by means of a spring 45. The other end of lever 44 is connected to a collar A set on shaft 34, shaft 34 being loosely and slidably mounted in bearings not shown wherebv when the magnet -A L, 7 3 J? t.

is energized, which happens when the carbons approach so as to complete the arc circuit, the magnet draws the armature end of the lever to itself, thus imparting a sudden endwise thrust to shaft 34 and causing thereby an immediate limited separation. ofA the cai-bons. In the motor circuit is a starting means of whichl the apparatus can be soset that it Willi maintain any desired voltage across the arc.

The arc circuitf includes4 the rheostat, the striking magnet and the positive andnegative carbons andLin-shunt the auxiliary field of motor 3a The motor circuit includes motors-. r 2^ and 3- andf the magnetic clutch which4 are connected] in multiple through the automatic .starting box.

Assuming a- {iQ-inch searchlight requiring two hundred amperesat volts across the arc to be supplied with current from rt-,125 volt directA current plant some distance away, the motorsv of the lamp mechanism being` Wound for 110 volts. To avoid the use of heavy copper Wire separate feeders are ledzfromthe plant to the arc circuit and tothe motor circuit. The size of Wirevfor the arc circuit is thenaffected'by tvvo factors, viz., safe-carrying capacity and a terminal voltage of 65 volts at the arc. The final adjustment of fixed voltage is made by means of the rheostat47,l By means of resistences-50, the fields ofmotors 2 and 3 are so adjusted that When the motor and arc circuitsare both energized and the voltage across the arc, which is also impressed on tlieAauX-iliary field Qof motor 3, is t'volts, the armature l2 is at rest.

A complete cycle of operationvofmy 'device under the assumed condition follows, starting With the carbons separated. The current in the arc circuit is flowing from the positive Wire through the rheo'stat 47, the striking magnet 43 and the auxiliary iield 25 of motor 8 to the negative wire but not through the carbons. rillie motors are started to draw the arc by' moving arm ofI the starting box 46 to the extreme l' t where it is held by the solenoid which if en` ergized by the current flowing in the arc circuit. rlhe current in the motor circuit is owing from the positive Wire through the armatures and shunt Fields of motors 2 and B and through the clutch coil 40, all of wvl" maarre' practically 'full voltage is impressed on the auxiliary ield25, making the field 'of motor 8 stronger' thannormal and producing a resultant rotation. of armature l2 in a direction to cause the carbons to feed together. Theclutchcoil 40, being energized,` attracts its disk armature 41 and locks the gear 39 tothe sha-ft of armature 12 so that the gear train is actuated by the movement of the armature and the carbons are brought to gether. AssoonI as thecarbons'touch` current-flows from the 4positive Wire through the rheostatf, striking magneti and carbons tol the negative Wire. This current causes the strik-ingmagnetto attract its armature, andthe-resultantl movement of the lever 44 imparts an endwise thrust to the-shaft 34; giving animmediatev measured separation tothe carbons and drawing anA arc.- Vhile the carbone are in contact, the; voltage at the terminals of the auxiliary'eld'coil 25 is O, andy the-lield'ofmotor 3-is made weaker than normal, causing the armature 12` to reverseautomatically and rotate-in the oppositedirection to its iieldt and tending to separate the. carbons. The action of the starting magnet, however, in drawing the arc quickly raises the voltage impressed on the auxiliaryfield Qiand'modiies the action of the armature 1Q.

' After the carbonshave beenseparated. by the striking magnet,the voltage across the arc ismaintained-at a constant value'by the action of armature l2 which rotates in one direction or the other, mcving-the-ca-rbons together or separating them automatically, according astiie voltage acrossfthearc'is above or belowtlienormal for which' adL justments havebeen made.

lli", during' the operation of the' lamp, the are circuitbe opened between .the generator andthe startingbox magnet, the starting box solenoid Will be denergized, releasing thehandle which` swings to the left under the impulseA of, a spring, thus opening the motor circuit. l/Vere it not for this ora'n equivalent connection it Will be seen that the weakened*ielcl'ofI motor 3 Wouldi cause the armature l2 to rotate in a direction te separate the carbons, until the supporting arms were jammed atthe 'ends of the threadL ed portionsof= the shafts 34and35.-

is'also found thataa similar jamming caribe occasioned by the inertiaof the armatin'e l-after the motor circuit has been opened if the gear 39 is splinedon the arnisnv ture shaft. ltl Willbe seen that this dif# culty is obviated by the electro-magnetic clutch 40 'Whichisdenergized When'the mc tor circuit-is opened, allowing the armature si Lft to turn freely in the gear 39 and stcpigfall motion-of the gear train.

:laying thusdescribed inyinvention'and its use, l clairnz- Il. in a electric regulator, an are circuit including lamp elements, means for eiecting a gradual movement of said elements to or away from each other according as the current through them varies, a motor circuit independent of the arc circuit comprising two motors, the armature of one motor fixed to and rotary with one element of the other motor, the other element of the latter motor being freely rotary, some of the iield magnet coils of the latter motor in circuit with said lamp and mechanism connected between said freely rotary element and said arc lamp for adjusting said lamp when the current through the same varies, and a starting boX, the solenoid of which is energized from the arc circuit, wherebywhen the arc ,circuit is opened, said solenoid is automaticall deenergized, the motor circuit is opene and further movement of the regulating mechanism is arrested.-

2. In an electric regulator, an arc circuit including lamp elements and means for effecting an abrupt measured separation of said elements, in combination with a motor circuit comprising two'motors, the armature .of one motor fixed to and rotary with one element of the other motor, the other element of the latter motor being freely rotary, some of the field motor coils of the latter motor being energized from the motor circuit and wound,to oppose the coils in shunt to the arc, some of the field magnet coils of the latter motor being ener 'zed from the motor circuit, some of the iie d'mngnet coils of the latter motor in circuit wlth said 11mg I and mechanism connected between sai freely rotary element and said lamp for adjusting said lamp elements when the current through the same varies, and an adjustable resista-nce located inthe motor circuit and connecting with the field coils of one of the motors, whereby the apparatus can be so set that it will maintain any desired voltage across the arc.

3. In an electric regulator, an arc circuit .including lamp elements, means for eiecting a gradual movement of said elements to or away from each other according as the current through them varies, a motor circuit independent of. the are circuit, comprising two motors, the armature of one motor fixed to and rotary with one element of the other motor, the other element of the latter motor being freely rotary, some of the iield magnet coils of the latter motor in circuit with said lamp, mechanism connected between said freely rotary element and said lamp for adjusting said lamp elements when the current through the same varies, and means operable by the opening of the arc circuit to open the motor circuit and arrest further movement of the adjusting mechanism.

In witness whereof, I have signed my name to this specification in presence of two subscribing witnesses this eighteenth day of February, 1910.

HENRY W. HOBBS.

In pesenceCo-T- mm MARY C. PAntmI" 

